Glucose hofrieostasis is prirharlly maintained by the intricate bsilance of the glucoregiilatory, pancreatic hormones insulin and glucagon. Type 1 diabetes meljitus resijlts fironn the autoimmune destruction of pancreatic beta cells vt/h|ch produce insulin. Currently, the onjy available cure for type 1 diabeties is pancreatic or iislet transplantation, A prihriary linnitatJbn of theise bona fide cures is the limited availability of pancreataand paricreatic islets from cadaver donors. Because of thjs bottleneck, much work has been perfonned with the goal of finding an aiternative source of insulin-producing cells as well as establishing riiethpds to stimulate proliferation bf islets harvissted for transplantation. The current application addresses the critical need to establish methods to increase pancreatic islet mass. If successful, nfiore patients with type 1 diabetes will benefit from islet transplantation and be free from this serious disease. We have recently discovered that the pf-btease-reslstant peptide trefoil factor 3 (TFF3) is a jgrpwth factor for pancreatic islets. Since the discovery of TFFS's ability to increase cell proliferation of pancreatic beta cells, vt/e have begun to uncover the signaling pathways that lead tO: this beneficial effect. However, much work remains to fully characterize these pathways and to perhaps reveal other pathways that can be exploited in order tb Increase pancreatic beta cell tmiass. Further, it is equallylmportantto continue to identify novel factors that have the abiJify to increase beta cell mass. In pursuit of these goals.the following specific aims are proposed: 1) to determine the role of EGFlreceptor signaling on TFF-3 induced beta cell proliferation, 2) to determine the ro\e of Gene 33/Mig-6/RALT in mbdulatlng EGF receptcr signaling and beta cell proliferation, and 3) to identify noverfactors that regulate pancreatic beta cell mass. The results of this work might increase the therapeutic efficacy of islettrahsplant^tlpn.: